JP2019100916A - Window surface detection sensor - Google Patents

Abstract

To provide a window surface detection sensor capable of precisely obtaining information on an outer surface of the vehicle window.SOLUTION: A camera 11 has a CMOS sensor 13 and a lens 14 for picking up an image of a windshield 2 from inside the vehicle to obtain information on an outer surface 2a of the windshield 2. An imaging surface 13a of the CMOS sensor 13 and the main plane 14a of the lens 14 are disposed in a non-parallel state to each other so as to be inclined to the car interior with respect to a plane where the focus plane Pm includes the outer surface 2a of the windshield 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a window surface detection sensor.

  Conventionally, a window surface detection sensor is known that detects raindrops on a vehicle window using the so-called Shine Proof principle (see, for example, Patent Document 1). The window surface detection sensor of Patent Document 1 sets the depth of field so as to include the outer surface of the vehicle window using the principle of shine proof by setting the imaging surface of the imaging device and the main surface of the lens in a non-parallel state. It is supposed to match.

JP, 2016-218044, A

  By the way, in the window surface detection sensor as described above, the depth of field is adjusted so as to include the outer surface of the vehicle window with the imaging surface of the imaging device and the main surface of the lens not in parallel. However, as a result of studies by the inventor, it has been found that the depth of field differs depending on the position. As a result, the background such as the road surface is in focus at the deep part of the depth of field, and there is a possibility that the information on the outer surface of the vehicle window can not be obtained with high definition.

  The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a window surface detection sensor capable of obtaining information on the outer surface of a vehicle window with high definition.

  A window surface detection sensor for solving the above-mentioned problem is a window surface detection sensor which has an imaging element and a lens and picks up an image of a vehicle window from the inside of the vehicle to obtain information on the surface of the vehicle window. The imaging surface of the element and the main surface of the lens are provided non-parallel to each other so that the focusing surface is inclined toward the vehicle interior with respect to the plane including the outer surface of the vehicle window.

  According to the above aspect, the imaging surface of the imaging device and the main surface of the lens are provided in a non-parallel state with each other such that the focusing surface is inclined toward the vehicle interior with reference to the plane including the outer surface of the vehicle window. The depth of field outside the vehicle can be set shallower at a position where the depth of field tends to be deeper. As a result, focusing on the road surface or the like can be suppressed, and information on the outer surface of the vehicle window can be obtained with high definition.

  In the window surface detection sensor, the imaging element and the lens are disposed closer to the upper side in the vertical direction of the vehicle window and are spaced apart toward the lower end side of the vehicle window, and the focusing surface is the imaging device It is preferable that the lower end side in the imaging range of is the inside of the passenger compartment.

  According to the above aspect, the lower end side at a distance from the imaging device and the lens in the focal plane is the inside of the vehicle compartment, so the depth of field outside the vehicle exterior is shallow on the lower side where the depth of field tends to be deep. It can be set near the outer surface of the vehicle window. As a result, focusing on the road surface or the like can be suppressed, and information on the outer surface of the vehicle window can be obtained with high definition.

  According to the window surface detection sensor of the present invention, information of the outer surface of the vehicle window can be obtained with high definition.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic cross section of the vehicle in one Embodiment.

  Hereinafter, an embodiment of a vehicle provided with a window surface detection sensor will be described. In the drawings, for convenience of explanation, part of the configuration may be shown exaggerated or simplified. Also, the dimensional ratio of each part may be different from the actual one.

  As shown in FIG. 1, the vehicle C is provided with a windshield 2 as a vehicle window so as to extend obliquely downward from the vehicle front side end of the roof panel 1 toward the vehicle front side. Further, on the lower surface of the roof panel 1 in the vehicle C, a rearview mirror 4 for confirming the rear from the driver's seat 3 is supported.

  In addition, the vehicle C is provided with a camera 11 as a window surface detection sensor for capturing an image of the windshield 2 from inside the vehicle C to obtain information on the surface of the windshield 2. The camera 11 has a housing 12, a CMOS (image) sensor 13 as an imaging device housed and held in the housing 12, and a lens 14 held so as to be exposed to the outside from the housing 12. The camera 11 is fixed to the roof panel 1 in the present embodiment so as to be disposed on the vehicle front side of the rearview mirror 4. Specifically, the camera 11 has a support 12a extending upward to support the housing 12, and the support 12a is fixed to the roof panel 1 such that the camera 11 is disposed on the vehicle front side of the rearview mirror 4 It is done. The rearview mirror 4 is disposed at the center of the vehicle C in the vehicle width direction (width direction of the windshield 2), and the camera 11 is also disposed at the center of the vehicle C in the vehicle width direction (width direction of the windshield 2).

  The imaging surface 13a of the CMOS sensor 13 and the principal surface 14a of the lens 14 are provided non-parallel to each other so that the focal plane Pm is inclined toward the vehicle interior with reference to the plane including the outer surface 2a of the windshield 2 ing. More specifically, the imaging surface 13a and the main surface 14a are provided in an inclined manner so that the lower end side in the imaging range is on the vehicle interior side. The imaging surface 13a and the main surface 14a are provided so as to be inclined such that the plane including the focusing surface Pm and the imaging surface 13a intersects with the main surface 14a on the straight line L. Although the outer surface 2a of the windshield 2 is actually curved and not a flat surface, the inclination between the imaging surface 13a of the CMOS sensor 13 and the main surface 14a of the lens 14 is determined using a plane closest to the curved surface. It is set. FIG. 1 is a schematic cross-sectional view of the vehicle C as viewed from the side (vehicle width direction), showing a plane including the imaging surface 13a as a straight line S1, and illustrating a plane including the main surface 14a as a straight line S2. It shows. Furthermore, in FIG. 1, a plane including the outer surface 2a of the windshield 2 is illustrated as a straight line S3, and illustrated as a straight line S4 including a focus plane Pm including a line S3 as a reference and inclined toward the vehicle interior. Because it extends in the direction, it is illustrated by a point.

  By setting it as the structure mentioned above, in the camera 11 of this embodiment, the depth of field D will be set on the basis of the said focus plane Pm. Note that the depth of field D is a range that can be considered to be in focus (in-focus), and the front depth of field D1 located on the front side (rear side in the vehicle C) with respect to the focus plane Pm This is a range obtained by adding the rear depth of field D2 located on the rear side (the front side in the vehicle C) with reference to the focal plane Pm. Further, the depth of field D of this example is shallower toward the upper end side of the windshield 2 within the imaging range of the camera 11 and deeper toward the lower end side.

  Therefore, as described above, the imaging surface 13a and the main surface 14a are inclined so that the lower end side in the imaging range of the focus plane Pm is on the vehicle interior side, the front depth of field D2 in the imaging range is front glass It will be set near the outer surface 2a of 2. Further, the depth of field D in this example is a position including the outer surface 2a in the imaging range.

  In addition, in the camera 11, the position P at which the imaging central axis J intersects the outer surface 2a of the windshield 2 so that the imaging central axis J faces the vertical direction side (in other words, obliquely downward) than the horizontal plane It is provided to be within the range H1 of the upper half of the glass 2. In addition, the range H1 of the upper half of the windshield 2 is a range between the upper end of the windshield 2 and the vertical center Z of the windshield 2 in detail.

Next, the operation of the vehicle C (camera 11) configured as described above will be described.
For example, when the lever switch SW provided in the vehicle is operated to the automatic position, the windshield 11 is periodically imaged by the camera 11 from the inside of the vehicle C. In FIG. 1, the imaging range (angle) by the camera 11 is illustrated by a broken line. When it is determined by the control unit (not shown) that raindrops or the like adhere to the windshield 2 based on the captured image, a wiper (not shown) is driven to wipe the windshield 2 and automatically raindrops. Etc. are removed.

The effects of this embodiment will be described.
(1) The imaging surface 13a of the CMOS sensor 13 and the principal surface 14a of the lens 14 are not parallel to each other so that the focal plane Pm is inclined toward the vehicle interior with reference to the plane including the outer surface 2a of the windshield 2 Because the depth of field D tends to be deep, the depth of field outside the vehicle can be set shallow. As a result, focusing on a road surface or the like can be suppressed, and information of the outer surface 2 a of the windshield 2 can be obtained with high definition.

  (2) Since the lower end side away from the CMOS sensor 13 and the lens 14 in the focal plane Pm is on the inside of the vehicle compartment, the depth of field D outside the vehicle exterior on the lower side where the depth of field D tends to be deeper (The rear depth of field D2) can be made shallow and set near the outer surface 2a of the windshield 2. As a result, focusing on a road surface or the like can be suppressed, and information of the outer surface 2 a of the windshield 2 can be obtained with high definition.

The above embodiment may be modified as follows.
In the above embodiment, the camera 11 is fixed to the roof panel 1 so as to be disposed on the vehicle front side of the rearview mirror 4, but may be fixed to another position. For example, it may be fixed to the inner surface of the windshield 2. Even in such a configuration, the camera 11 is disposed on the vehicle front side of the rearview mirror 4. Further, with such a configuration, for example, the working distance (the distance from the lens 14 to the outer surface 2a of the windshield 2) is shorter than that fixed to the roof panel 1 (see the above embodiment). The depth of field can be reduced (shallow). Therefore, it is possible to suppress that the background is in focus (in focus), which in turn can suppress erroneous detection.

Moreover, you may employ | adopt the structure which provides the camera 11 not only at the upper end side of the windshield 2 but at the lower end side of the windshield 2, such as the upper surface of a dashboard.
In the above embodiment, the camera 11 is disposed at the center of the vehicle C in the vehicle width direction (the width direction of the windshield 2) and on the vehicle front side of the rearview mirror 4. However, the invention is not limited thereto. It may be fixed at another position. That is, the camera 11 may be fixed near the driver's seat from the center of the vehicle C in the vehicle width direction, or fixed near the passenger's seat from the center of the vehicle C in the vehicle width direction. For example, by fixing the camera 11 closer to the driver's seat, it is possible to obtain information on the outer surface of the windshield 2 in a high definition in a range (eye point) corresponding to the driver's field of vision. Therefore, it is possible to determine with high accuracy whether raindrops or the like are attached in a range (eye point) corresponding to the driver's field of vision, and by keeping the wiper interlocked, in particular, the driver's field of vision is kept good. It becomes possible.

  In the above embodiment, although not particularly mentioned, the imaging device (CMOS sensor 13) may have sensitivity to the infrared light region. Specifically, for example, an InGaAs image sensor having sensitivity to a near infrared light region may be adopted as the imaging device. In this case, it is possible to determine with high accuracy whether or not raindrops (water) are attached because water absorbs infrared light. Although the windshield 2 has a function of cutting infrared light having a wavelength of 3000 nm or more, infrared light can be obtained by using an imaging device corresponding to a near infrared light region such as an InGaAs image sensor. Even when used for a windshield 2 having a cutting function, the occurrence of problems can be avoided.

  Further, in this case, a filter member may be provided to prevent transmission of light in a region other than the infrared light region directed to the imaging device. Specifically, as a filter member, for example, a visible light cut filter that transmits visible light but transmits infrared light may be provided. In this way, it is possible to determine with high accuracy whether or not raindrops (water) are attached.

  In the above embodiment, although not particularly mentioned, the depth of field D is preferably about 10 mm. In this way, for example, it is possible to detect (estimate) the thickness of a raindrop. In addition, for example, even if the attachment angle of the camera 11 is slightly deviated, the deviation can be absorbed to suppress a decrease in detection accuracy. Also, for example, the influence of the curvature of the windshield 2 (vehicle window) can be absorbed to suppress the decrease in detection accuracy. Of course, the depth of field may be 10 mm or more, or 10 mm or less.

In the above embodiment, the camera 11 picks up an image of the windshield 2 from the inside of the vehicle C, but may pick up another vehicle window such as a rear glass.
In the above embodiment, the image sensor is the CMOS sensor 13. However, the present invention is not limited to this, and may be changed to another image sensor such as a CCD (image) sensor.

  In the above embodiment, the wiper is driven when it is determined that raindrops or the like are attached to the windshield 2 based on the captured image. However, the captured image may be used for other applications. Also, the captured image may be used to determine whether or not insects and the like other than raindrops are attached.

  In the above embodiment, the camera 11 is described as having only the lens 14 exposed to the outside, but the present invention is not limited to this, and the camera may be a camera having a lens also inside the housing 12, The lens (principal surface) and the imaging surface 13a may be inclined to use the principle of shine proof.

  -The above-mentioned embodiment and each modification may be combined suitably.

  Reference Signs List 2 windshield (vehicle window) 2a outer surface 11 camera (window surface detection sensor) 13 CMOS sensor (imaging element) 13a imaging surface 14 lens 14a main surface C vehicle , Pm ... Focus plane.

Claims (2)

A window surface detection sensor having an imaging element and a lens, for capturing an image of a vehicle window from inside the vehicle to obtain information on the surface of the vehicle window,
The imaging surface of the imaging element and the main surface of the lens are provided in a non-parallel state with each other such that the focusing surface is inclined toward the vehicle interior with reference to a plane including the outer surface of the vehicle window. Window surface detection sensor. The imaging element and the lens are disposed vertically upward in the vehicle window and are spaced apart toward the lower end of the vehicle window.
The window surface detection sensor according to claim 1, wherein a lower end side in an imaging range of the imaging element is on a vehicle interior side in the focusing plane.